1. Field of the Invention
The present invention relates to mixtures of halogenated alkyl phosphate esters containing aliphatic bromine and chlorine which may be used to flame-retard polymeric systems such as flexible polyurethanes, reaction injection molded polyurethanes, polyvinyl chloride, textile fibers, and poly-(methylmethacrylate), and the like.
2. Description of the Prior Art
The need to reduce the flammability of polymeric systems while not adversely affecting the chemical, physical and mechanical properties or the appearance of polymeric systems is disclosed in the Encyclopedia of Polymer Science and Technology, Volume 7, pp. 1-3 and the The Encyclopedia of Chemical Technology, 3rd Edition, Volume 10, pg. 348.
Phosphorous-halogen systems have been widely used to flame retard polymeric systems. For example, the use of certain pentavalent phosphate esters containing bromine and chlorine as flame retardants is taught by Birum, et al., U.S. Pat. No. 3,132,169. The compounds of Birum are selected from the general formula: ##STR2## wherein R is selected from the class consisting of hydrogen, alkyl and haloalkyl radicals of from 1 to 2 carbon atoms, R' is selected from the class consisting of hydrogen, alkyl and haloalkyl radicals of from 1 to 5 carbon atoms, R" is selected from the class consisting of R' and hydrocarbyloxymethyl radicals of from 1 to 8 carbon atoms, wherein one R" at a pair of adjacent carbon atoms must be hydrogen, and n is an integer from 0 to 1.
Other patents disclosing halogenated phosphate esters include Birum U.S. Pat. Nos. 3,192,242 and 3,344,112; Carpenter U.S. Pat. No. 3,324,205; Jenkner et al. U.S. Pat. No. 3,781,388; Dow et al. U.S. Pat. No. 3,830,886; Wilkinson U.S. Pat. No. 3,997,449; Stanaback U.S. Pat. No. 4,046,719; Albright U.S. Pat. Nos. 4,083,826 and 4,240,953; and West German OS Pat. No. 2,416,663. Applicants' own U.S. Pat. No. 4,083,825 discloses the use of bis(2-chloroethyl) 2,2-dimethyl-3-bromopropyl phosphate as a flame retardant for polyurethane foams.
None of the foregoing halogenated alkyl phosphate esters are believed to perform as effectively as desired as flame retardant additives. Furthermore, numerous halogenated alkyl phosphates containing aliphatic bromine have been determined to be mutagenic by the Ames test. On Apr. 28, 1977, the Consumer Products Safety Commission, acting under the Federal Hazardous Substances Act, banned the sales of children's sleepwear treated with the flame-retardant tris-(2,3-dibromopropyl) phosphate ("Tris"). In explaining this action, the Commission cited the two-year feeding tests by the National Cancer Institute that linked Tris to kidney cancer in mice and rats. It also cited studies showing that Tris, when tested in the Ames Test, was mutagenic in bacteria and, thus, possibly carcinogenic in humans.
It is, thus, a primary object of this invention to provide highly effective flame retardant mixtures of halogenated alkyl phosphates.
It is another object of the present invention to provide a mixture of halogenated alkyl phosphate esters containing aliphatic bromine which are not mutagenic by the Ames Test.
It is also an object of the present invention to provide effectively flame-retarded polymeric systems which do not possess any undesirable chemical, physical and mechanical properties and whose appearance is substantially unchanged by the flame retardant that is employed.